Question

Analytical Chemistry

Topic: Spike Recovery

Question: Explain why a recovery significantly greater than 100% or significantly less than 100% is possible.

Answer 1

Significantly greater:

- Due to humidity and human/methodology errors

i.e.

% X = mass of X / total mass * 100%

if initial "total" mass was 10.5 g

and we recovered 10.6 g, then, clearly X has extra mass, i.e. humidity of other compounds

- Less than 100%: since method/nature will not allow us to obtain 100% fro the product

example:

extraction of A in water/ether extraction

A will always remain in water + ether... so recovery of 100% of A in water will be impossible